A Tough World!

These brain teasers rely on your ability to recognize groups of common attributes. For each of these puzzles you'll need to figure out why the words or letters are grouped as they are. Sometimes you will be asked to pick the odd-one-out or to place a new word into the correct group.

Comments

My first thought was that Julius was the only emperor that didn't rule in AD, which does answer the question . . . but then I noticed that it didn't really fit the title, and thought some more to get te right answer! Great Teaser!!